Laundry detergent compositions, contained within a water-soluble pouch, are seeing wider use among consumers for reasons of convenience. Consumers are attracted to such single dose products because such products are less likely to result in spillage or dripping. Further, the unit dose laundry detergent pouches are advantageous since the consumer does not come into direct contact with the ingredients of the composition. Pouches associated with these products are typically composed of poly(vinyl alcohol) or poly(vinyl alcohol) copolymer films which can dissolve in water over a matter of seconds. The high aqueous solubility of such films necessitates a payload composition that contains a minimum amount of water. Typically, such compositions contain less than 10% water by weight.
It is generally believed that high water content liquid laundry detergents are incompatible with water-soluble films because of their water content. Thus, the attendant advantages of high water content liquid laundry detergents over other forms of laundry detergents such as granules, pastes, gels, and mulls have not been available in water-soluble unit dosage form. The advantages of liquid laundry detergents over granules, pastes, gels, and mulls include their aesthetic appearance and the faster delivery and dispersibility of the detergent ingredients to the laundry wash liquor, especially in a cool or cold water washing process.
The smaller amounts of water contained in water soluble pods have implications for both formulation and wash performance. For example, a smaller amount of water can limit the ability of certain materials to be incorporated into the composition, e.g. salts, water-soluble polymers (like anti-redeposition polymers), and water-soluble dyes. It is also well-known that removal of the chemical reactives in the payload are correlated with the extent of dissolution. As active ingredients in anhydrous formulations may not be released into the wash until full dissolution occurs, unit dose “pods” with higher water concentrations may exhibit faster action in the wash. Finally, as water is typically the least expensive component in a formulation, it is advantageous from a cost standpoint to employ the maximum amount of water, while still maintaining the desired performance.
There is a need, then, for unit dose systems with a level of water higher than that typically found in the prior art.